.flash-messages {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 9999;
    padding: 10px 20px;
    background: transparent;
}

.flash-messages .alert {
    margin-bottom: 10px;
    border-radius: 4px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

.flash-messages .alert-danger {
    background-color: #f8d7da;
    border-color: #f5c6cb;
    color: #721c24;
}

.flash-messages .alert-success {
    background-color: #d1edff;
    border-color: #bee5eb;
    color: #0c5460;
}

.flash-messages .alert-warning {
    background-color: #fff3cd;
    border-color: #ffeaa7;
    color: #856404;
}

.flash-messages .alert-info {
    background-color: #d1ecf1;
    border-color: #bee5eb;
    color: #0c5460;
}

/* 确保flash消息不会被header遮挡 */
body.has-flash-messages {
    padding-top: 80px;
}

/* 动画效果 */
.flash-messages .alert {
    animation: slideDown 0.3s ease-out;
}

@keyframes slideDown {
    from {
        transform: translateY(-100%);
        opacity: 0;
    }
    to {
        transform: translateY(0);
        opacity: 1;
    }
}